The invention relates to the technical sector of article counting and validating machines, in particular pharmaceutical articles, such as, though not limited to, lozenges, pills, tablets, capsules, pastilles or similar products.
In particular, the present invention relates to a method for counting and validating articles and an apparatus for actuating the method.
Various type of medicines are marketed, contained in bottles, with the aim of maintaining the integrity and preserving the sterility thereof, the filling of which is realized by special automated machines. Should the medicines be in the form of discrete articles and thus not in liquid or gassy form such as syrups or aerosols, the problem of having to count them arises, in order to control the quantity introduced into the respective bottles, and make sure the articles are singly whole.
The critical aspect of this problem is obvious on considering that the adoption of automated machines has the aim of rendering the above-described filling process not only more efficient but especially faster.
Typically, machines for filling the bottles with pharmaceutical articles comprise feeders constituted by linear vibrators which transport the articles towards a filling station, comprised in the machine, in which the bottles the pharmaceutical articles are destined for are located.
These feeders can be, for example, conformed such as to exhibit a multiplicity of conveying grooves, each having a substantially V-shaped transversal section for housing the loose articles, which advance along the grooves without piling up, thanks to the linear vibration.
It is clear that a section of the machine that is at the same time downstream of the feeder and immediately upstream of or positioned at the filling section is the best location for an article counting and validation device.
A known method for counting and validating single pharmaceutical articles to be sold in bottles and a device for performing the task are described in patent document EP 1251073.
In this method the articles borne by the feeders, once having reached the filling section, are left to fall by force of gravity, for subsequent introduction into the bottles. The articles, not being piled one on another, fall one at a time; this means that each of them, thanks to the acceleration impressed on them by the force of gravity, is distanced from the next at the moment of dropping.
A TV camera is located downstream of the feeder, at a certain point in the trajectory of the fall, and in proximity of the articles.
The camera is associated to a control unit, which has the function of comparing the profile of each falling article framed by the camera, with the profile provided to the camera as an example of a whole article. If the control unit detects, on a profile of one of the falling articles, a difference with respect to the whole article defined as meaningful on the basis of given parameters, the article is defined as non-whole.
The stage of comparison is made possible by a distancing between the falling articles, as mentioned above.
Before the articles enter the bottle, and in a zone of the machine which is upstream of the bottles themselves, the articles are counted by special optical sensor organs, such as for example photovoltaic cells, a functioning of which is assumed to be known.
An effective validation of the articles in the prior art can be done only by obtaining a considerable optical contrast between the articles themselves and that which constitutes the background in the frame captured by the camera.
Given the velocity at which the bottles have to be filled, in order to obtain good machine performance, the only adjustments possible for improving the contrast are:                placing a special contrast surface, for example for achieving a chromatic contrast with the articles to be validated, in an position (in relation to the camera) opposite the fall trajectory, and        using light sources for illuminating the fall trajectory, at the same height as the camera, positioning side-lighting with respect to the contrast surface, such that the shadows of the falling articles project thereon.        
With these adjustments, there is a discontinuity between the luminosity of the article to be validated and the luminosity of the contrast surface, and this is accentuated around the edge of the profile thereof, which from the point of observation of the camera appears to be at least partly surrounded by shadows.
From the above description it can be seen that the solution of the prior art can be effective in counting completely opaque pharmaceutical articles and in obtaining a correct validation but, since only an optical technology is used, it cannot in any way achieve the technical aims of counting and validating pharmaceutical articles which are entirely or partly translucent or transparent (a representative example is that of drugs contained in a gelatin capsule).
A second considerable limitation which hinders the efficacy of the above-described solution consists in the fact that it does not make available any means or process which can prevent an object of a different nature from those of the specific pharmaceutical articles from reaching a bottle. By way of example, though not exhaustive, reference is made to a case of a pharmaceutical product which is inadvertently arranged on the conveyor groove of the feeder in which other specific pharmaceutical articles are arranged, destined for specific bottles, exhibiting the same shape, for example because they are contained in a same type of capsule but having a totally different formula. The dangers correlated to an eventuality of this type are, as will be anticipated, of considerable entity; let it suffice to think of what risks a person runs when unknowingly ingesting a pharmaceutical product comprising an active ingredient which is totally different from that of the prescribed medicine.